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Commit b1e4d20c authored by Michal Schmidt's avatar Michal Schmidt Committed by Rusty Russell
Browse files

params: make dashes and underscores in parameter names truly equal 

The user may use "foo-bar" for a kernel parameter defined as "foo_bar".
Make sure it works the other way around too.

Apply the equality of dashes and underscores on early_params and __setup
params as well.

The example given in Documentation/kernel-parameters.txt indicates that
this is the intended behaviour.

With the patch the kernel accepts "log-buf-len=1M" as expected.
https://bugzilla.redhat.com/show_bug.cgi?id=744545



Signed-off-by: default avatarMichal Schmidt <mschmidt@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (neatened implementations)
parent 37252db6

include/linux/moduleparam.h

+20 −0
Original line number Diff line number Diff line
@@ -262,6 +262,26 @@ static inline void __kernel_param_unlock(void) 
			    .str = &__param_string_##name, 0, perm);	\

	__MODULE_PARM_TYPE(name, "string")



/**

 * parameq - checks if two parameter names match

 * @name1: parameter name 1

 * @name2: parameter name 2

 *

 * Returns true if the two parameter names are equal.

 * Dashes (-) are considered equal to underscores (_).

 */

extern bool parameq(const char *name1, const char *name2);



/**

 * parameqn - checks if two parameter names match

 * @name1: parameter name 1

 * @name2: parameter name 2

 * @n: the length to compare

 *

 * Similar to parameq(), except it compares @n characters.

 */

extern bool parameqn(const char *name1, const char *name2, size_t n);



/* Called on module insert or kernel boot */

extern int parse_args(const char *name,

		      char *args,

init/main.c

+2 −2
Original line number Diff line number Diff line
@@ -163,7 +163,7 @@ static int __init obsolete_checksetup(char *line) 
	p = __setup_start;

	do {

		int n = strlen(p->str);

		if (!strncmp(line, p->str, n)) {

		if (parameqn(line, p->str, n)) {

			if (p->early) {

				/* Already done in parse_early_param?

				 * (Needs exact match on param part).
@@ -392,7 +392,7 @@ static int __init do_early_param(char *param, char *val) 
	const struct obs_kernel_param *p;



	for (p = __setup_start; p < __setup_end; p++) {

		if ((p->early && strcmp(param, p->str) == 0) ||

		if ((p->early && parameq(param, p->str)) ||

		    (strcmp(param, "console") == 0 &&

		     strcmp(p->str, "earlycon") == 0)

		) {

kernel/params.c

+14 −7
Original line number Diff line number Diff line
@@ -67,20 +67,27 @@ static void maybe_kfree_parameter(void *param) 
	}

}



static inline char dash2underscore(char c)

static char dash2underscore(char c)

{

	if (c == '-')

		return '_';

	return c;

}



static inline int parameq(const char *input, const char *paramname)

bool parameqn(const char *a, const char *b, size_t n)

{

	unsigned int i;

	for (i = 0; dash2underscore(input[i]) == paramname[i]; i++)

		if (input[i] == '\0')

			return 1;

	return 0;

	size_t i;



	for (i = 0; i < n; i++) {

		if (dash2underscore(a[i]) != dash2underscore(b[i]))

			return false;

	}

	return true;

}



bool parameq(const char *a, const char *b)

{

	return parameqn(a, b, strlen(a)+1);

}



static int parse_one(char *param,